Methods, apparatuses, and articles of manufacture consistent with the present disclosure relate to extracting error for peak signal to noise ratio (PSNR) computation in an adaptive scalable texture compression (ATSC) encoder.
Generally, in image compression, an uncompressed image is processed to obtain a compressed image. The image processing includes application of one or more algorithms to the uncompressed image. As an example, one such algorithm for image compression is joint photographic experts group (JPEG), which standardized the algorithm.
One type of image is called a texture map or a texture. A texture map is an image that is applicable to a surface of a two-dimensional or three-dimensional object (for example, an object that is represented in a virtual space by wireframe model that includes one or more polygons). Similar to images, texture maps are compressed using one or more image compression techniques to obtain compressed textures which are easily stored in a database or quickly communicated over a network. Advanced scalable texture compression (ASTC) is a standard compression algorithm developed by ARM and is predominantly used for texture compression.
In general, peak signal to noise ratio (PSNR) affects image compression or texture compression as the PSNR reflects the compression quality. For achieving efficient compression, the value of the PSNR should be high. Hence, it is advantageous to compute the PSNR of the image which is being encoded while the encoding is in progress.
The existing texture compression techniques use block-based encoding. In order to compute the PSNR for a particular block mode for encoding, the error difference between the original raw data to the reconstructed data is derived. The error difference between the raw image data and reconstructed data is due to the compression process which is lossy. The compressed block is decoded through the decoder and the reconstructed raw data is obtained. The difference between the raw image data and the reconstructed data is computed for extracting the error. Thus, there is a disadvantage in that a decoder is required for decoding the encoded image for extracting the error. Because the decoder is required, additional silicon hardware area is required and also significant power for operating the decoder is consumed.